Floating dry dock



J. 5. CRANDALL 2,465,851

FLOATING DRY Docx 5 Sheets-Sheet 1 IN V EN TOR.

March 29, 1949.

Filed Sept. 50, 1944 March 29, 1949. J. s. C RANDALL FLOATING DRY DOCK 3Sheets-Sheet 2 Filed Sept. 30, 1944 m m m N 1 FI I I I .lI- I .lll I n:

mummw March 29, 1949. J. 5. CRANDALL 2,465,851

' FLOATING DRY DOCK Filed Sept. 30, 1944 5 Sheds-Sheet 3 Patented Mai.29, 1949 UNITED STATES PATENT OFFICE FLOATING DRY DOCK James StuartCrandall, Lexington, Mass, assignor to Crandall Dry Dock Engineers Inc.,Cambridge, Mass, a corporation of Massachusetts Application September30, 1944, Serial No. 556,565

Claims. 1

This invention relates to improvements in floating dry docks.

More particularly it provides improvements in self-docking floating drydocks which customarily are made in sections and which are designed sothat some one or more sections thereof may be conditioned and utilizedfor elevating and supporting one or more other sections thereofsufficiently above the water surface so that work may be done onnormally submerged regions of the elevated sections.

It has been proposed heretofore to provide a main central section of drydock and separable end sections, each constituting in itself a completedry docking unit with means for submerging it or for rendering itbuoyant at will. But, in order to clock a vessel of any sizeableproportions, the sections are connected together so that all of thesections act as a unitary floating dry dock.

Also it has been proposed heretofore to design the dry dock sections sothat the end sections can be utilized to elevate and buoy up the centralsection thereby to get its under surface suitably spaced above the waterlevel to permit inspection thereof and work to be done thereon whennecessary. But these prior proposals have involved a submergence andpositioning of the end sections sufficiently under the central sectionso that the center of buoyancy of the end sections coincides with thecenter of application of the lifting force. The end sections too,according to prior disclosures, may be floated between the side wings ofthe central section while the latter is suitably submerged, after whichthe central section can be rendered buoyant to lift the end sectionsthereon above the water level.

It is among the objects of my present invention to provide aself-docking floating dry dock having one or more central orintermediate sections, and two end sections, each section constitutingin itself a complete buoyant unit having provision for endwiseconnection to an adjacent section in a manner which provides asubstantial transverse passageway between the sections, extending fromside to side thereof.

I provide an upper horizontally projecting portion at an end of onesection and a lower horizontally projecting portion at an end of anothersection which is to be connected to the first mentioned section. Theseprojecting portions are disposed in vertically relatively widely spacedrelation, and suitable mechanical connections secure them in the saidspaced relation as well as securing the sections endwise together.

Another object of the invention is to provide a construction of docksections whereby sections thereof may be associated endwise together ina manner which provides a couple tending to rotate one of the sections,and means connecting the sections together and balancing the moment ofthe said couple.

The mentioned vertically spaced projecting end portions on connecteddock sections constitute means, spaced from the centers of buoyancy ofthe respective sections, for inter-engagement of the ends of adjacentsections, and the mechanical connections securing the sections togetherresist and balance the resulting couple.

A further object is to provide a sectional selfdocking floating dry dockany section of which may be dry docked on one or more other sectionsthereof by a mere vertical relative shifting of the endwiserelationships of adjacent sections, so that the sections may bedetachably rigidly connected together with either one of two adjacentsections substantially elevated relative to the other section.

I provide the ends of adjacent sections with a structure which permitstheir relative vertical shifting, and provide mechanical means wherebythe sections may be secured together in any of a plurality of endwiserelationships.

A feature is that when adjacent sections are shifted vertically but notlongitudinally relative to each other from their normal vessel-dockingrelationship, the previously mentioned transverse passageway, from sideto side between the sections, and having substantial dimensions, may bepreserved during operations of dry docking any one or more of the docksections.

Still another object is to provide a sectional self-docking floating drydock whose central or intermediate section has a horizontal endprojection relatively high up on the section for engaging over the topend region of an end section of the dock, and whose said end section hasa horizontal projection relatively low down on the section for engagingunder the bottom end region of the adjacent central or intermediatesection, both of said regions of engagement of projections beingsubstantially spaced from the center of buoyancy of said end section indirection toward the said central or intermediate section, whereby thecentral or intermediate section may be dry docked on two similar endsections.

An additional object is to provide floating dry dock sections havingprovision for endwise connection of the end sections to a central orintermediate section or sections for dry docking of the end sections onthe central or intermediate section or sections. It is a feature of mypreviously mentioned construction, in which each end section has a lowerhorizontally projecting portion and the adjacent end of a central orintermediate section has an upper horizontally projecting portion, thatthe said central or intermediate section needs to be lowered orsubmerged relative to the adjacent end section a Vertical distancesufiicient to partially close the transverse passage normally providedbetween the upper and lower projecting portions of the sections, and thesections may be secured in their new relation by suitable mechanicalconnections capable of successfully resisting the weight of an endsection when the central or intermediate section is elevated to lift theend section a suitable distance clearof the water.

A still further object is to provide a self-docking sectional floatingdry dock whose end sections practically and conveniently may be longerthan has been feasible with prior constructions.

It is, moreover, my purpose and object generally to improve theconstruction of self-docking sectional floating dry docks.

In the accompanying drawings:

Figure 1 is a top plan View of a floating dry dock embodying features ofmy present invention, a central part thereof being broken away;

Figure 2 is a side elevation of the floating dry dock of Figure l, withthe dock sections connected in their normal relationships for use of thedock for dry docking a vessel;

Figure 3 is a side elevation showing the preferred relationships of thedock sections when connected for dry docking of the central section onthe two end sections;

Figure 4 is a side elevation showing the relationships of the docksections when connected for dry docking of the two end sections on thecentral section;

Figure 5 is a typical cross-sectional view through any one of the drydock sections;

Figure 6 is a fragmentary view showing, in elevation and on a largerscale, one of the mechanical connections between sections;

Figure '7 is a top plan of Figure 6 and Figure 8 is a fragmentary sideelevation showing .a modified arrangement and relationship of sectionsfor dry docking the central section on the end sections.

Referring to the drawings, the dry dock therein represented comprises acentral section l and two end sections I2 and I4, although it will beobvious that two or more central or intermediate sections suitablyconnected together may be utilized in place of the single centralsection l0 illustrated in the drawings. Also it should be understoodthat the dock sections I0, l2 and 14 may be of either wood or metalconstruction or may be a combination of wood and metal, or of othersuitable materials, without departing from the spirit and scope of mypresent invention.

Each of the dock sections Ill, I2 and I4 preferably has across-sectional construction generally as represented in Fig. of thedrawings, comprising a hollow bottom or platform indicated generally at[6 and two upstanding hollow wings l8 and 20 extending along oppositesides of the platform, between which side wings and over the platform avessel may be floated while the dock is submerged, to be thereafterlifted clear of the water by rendering the dock sections sufficientlybuoyant to lift the Vessel above the surface of the water.

Each dock section constitutes in itself a complete buoyant dry dockingunit with the custom- 4 ary mechanism and connections for pumping wa'ter into and out of the interior buoyancy compartments.

My present invention has to do primarily with the structure at the endregions of the respective dock sections, the connections by whichadjacent sections are connected together, and the relationships ofconnected sections for different dry docking operations Referring moreparticularly to Figs. 1 and 2 of the drawings, wherein the sections areconnected for use of the dry dock in docking a vessel, each end of thecentral section I0 has an upper horizontally projecting part 22, and theadjacent end of each end section l2 and M has a lower horizontallyprojecting part 24 and 26 respectively. Each of the projecting parts 22,24 and 26 preferably has depth from its top to its bottom a substantialamount less than one-half the total depth of its section, so that whenthe sections are aligned with their bot-tom surfaces in a common plane,as in Fig. 2, a substantial transverse space 28 is provided between theprojecting parts 22 of central section l0 and the projecting parts 24and 2B of the end sections 12 and I4. Also the ends of the main bodiesof the adjacent sections are spaced apart a distance approximating thedistance of horizontal projection of the parts 22, 24 and 2 6, so thatthe transverse space 28 constitutes a transverse passageway of generallyrectangular shape extending from side to side of the dry dock and whichcan have dimensions permitting passage of workmen through the passagewaywhose floor is the top surface of a projecting part 24 or 28 of an endsection.

Preferably all of the horizontally projecting parts 22, 24 and 26 are ofthe same or approximately the same length so that, when the sections arealigned as in Fig. 2, the upper projecting parts 22 of central sectionII extend approximately to the adjacent end of the main body of endsections 12 and I4, and the lower projecting parts 24 and 26 of endsections I2 and I4 extend approximately to the adjacent ends of the mainbody of central section II]. According to my invention an uppermechanical connection 30 is provided at each side of the dock detachablysecuring each end section to the central section,

and a similar lower mechanical connection 32 is provided at each side ofthe dock detachably securing each end section to the central secton.

The mechanical connections at 30 and 32 necessarily must be capable ofsuccessfully resisting shearing and other stresses which may be imposedupon them in normal uses of the dock for dry docking a vessel, includinga condition where the major part of a vessels weight may be applied tothe central section It). In Figs. 6 and '7 of the drawings, eachconnection 30 and 32 is shown as comprising. a rugged and strongrelatively short channel member 34 secured as by bolts 36 to onesection, and a similarly rugged and strong coacting member 3% secured asby bolts 40 to the other section and having a projecting car 42 forengaging within the channel of member 34. Holes 44 in the side walls ofthe channel member 34 and a hole 46 in ear 42 of member 38 are adaptedto be brought into register for reception of a removable locking bolt 48which may be retained by a cotter pin 50 or by any other suitable meanswhich permits ready disconnection of the sections. The members 34 and 38and the locking bolt 48 at each connection can be made of sufi'icientsizes and strengths so that the four connections at each juncture ofdock sections can efiectively maintain the needed substantially rigidinter-connection of sections under all conditions of use.

It is an important feature of my invention and disclosed constructionthat the central section conveniently and effectively may be itself drydocked on the end sections l2 and, M, and that the end sections l2 and Mmay be conveniently and effectively dry docked on the central sectionFig. 3 illustrates the preferred manner of dry docking the centralsection on the end sections, and Fig. 4 shows how the two end sectionscan be dry docked on the central section.

In Fig. 3, the end sections l2 and I4 have been submerged sufficientlyrelative to the central section Ill so that the lower projecting parts24 and 26 can be moved under the ends of the main body of centralsection it. Simultaneously the adjacent end of the main body of each endsection moves under the upper projecting parts 22 of the centralsection. Mechanical connections 52 and 54, similar to the connections 30and 32, detachably secure the sections together as a substantially rigidunit.

In the arrangement of Fig. 3, it is important that the lower projections24 and 26, in effect, shall engage the overlying portion of the section[0, and that the end regions of the end sections which underly the upperprojections 22 shall, in effect, be in engagement. Hence, the fillerblocks 56 are provided so that lifting forces are applied directly tothe central section through the blocks 56.

It will be obvious that the end sections [2, l4

need to be submerged relative to the central section only a relativelysmall amount, and need to be displaced longitudinally from their normalrelations to the central section only a relatively small amount, whenbeing moved to their positions of Fig. 3. The regular pumping equipmentand connections for all sections are readily accessible for use in thisoperation of dry docking the central section.

In Fig. 3, it will be obvious that the center of buoyancy of each endsection l2, I4 is a substantial distance outward from the center ofapplication of load thereto, so that a couple exists which tends torotate each end section. The mechanical connections 52, 54 at oppositeends of the dry dock resist and balance the moments of the couples whilethe main lifting forces are transmitted through the blocks 56.

A dry docking of the end sections on the central section, as in Fig. 4,is even more simple than the previously described dry docking of thecentral section. In Fig. 4, no relative longitudinal movement ofsections is required, but only a submerging of the central sectionrelative to the end sections until the mechanical connections at 58,6|], similar to the connections 30, 32, and 52, 54, can be effected. Inthis case, the end sections are lifted bodily by the central sectionwith the full weight of an end sectioncarried at the connections 58, 60at each end. Inasmuch as an end section is considerably smaller and muchlighter than the central section, the mechanical connections at 5B, 60can be made capable of sustaining the total weight of an end section.

Because the length of each end section [2, I4 is substantially less thanthe space between the side wings i8, 20 of the central section, the endsections may, if desired, be dry docked on the central section byturning them through ninety degrees from their normal positions and thenfloating them between the wings of the central section while the lattersection is suitably submerged, after which the central section can berendered buoyant to lift the end sections thereon clear of the water. Insuch a case, the fantail platform 64 at each end of the dry dock firstwill be moved onto the end section with which it serves, between theside wings thereof. The said platforms may be removable or hinged forthis purpose.

In Fig. 8, I show how the central section may be dry docked on the endsections without any longitudinal relative shifting of the sections. Theend sections l2, M are merely lowered vertically relative to the centralsection l0, and connections 66, 68 secure the sections together. In thiscase, however, the advantage of the couples of the Fig. 3 arrangement isabsent and the mechanical connections at 66, 68 must be capable ofsustaining the entire weight of the central section.

I claim as my invention:

1. A floating dry dock comprising a plurality of buoyant sectionsdetachably secured together in end to end relation, one of said sectionshaving an upper horizontally projecting part at one end, and anotheradjacent section having a lower horizontally projecting part at its endwhich is toward the first mentioned section, said lower projecting partextending throughout the width of its section, and each said projectingpart having depth substantially less than one-half the depth of itssection, said lower projecting part of one section being disposed belowsaid upper projecting part of the other section, and the end of eachsaid projecting part of a section being detachably secured to anadjacent wall of another section in a relation providing a substantialspace between said projecting parts, said space extending from side toside of the dry dock and constituting a passageway of which the saidlower projecting part of one section constitutes the floor.

2. A floating dry dock comprising a plurality of buoyant sections in endto end relation, one section having a horizontally projecting part atone end in the plane of the bottom of the section and extendingthroughout the width of its section, and the adjacent section havingupstanding side wings and each said wing having a horizontallyprojecting part approximately in the plane of the top of a wing, meansfor detachably securing the sections together with said wing projectingparts of one section disposed above the full width projecting part ofthe other section in one predeterminecl spaced relation providing atransverse passageway between the sections, and other means fordetachably securing the sections together with said projecting partsdisposed one above the other in a different predetermined spacedrelation providing a smaller but substantial transverse passagewaybetween the section.

3. In a self-docking floating dry dock, a relatively long centralbuoyant section and two shorter end sections, one at each end of thecentral section, and means at the adjacent ends of the sections for drydocking support of the central section on the two end sections, saidmeans comprising a projection relatively high up on each end of thecentral section and a projection relatively low down on the adjacent endof each end section each said low down projection constituting anextension of the main buoyancy part of an end section and extendingthroughout the width of its section, the top end portion of each menaceend sectionbeing engaged under a saidlngha-up projection. of the centralsection; and the said low down projection on each end section beingengaged. under abottom end portion of the centralsection whereby thecentral section rests at each end on a buoyant part of each end section,the center of buoyancy of each endsection being spaced a substantialvdistance outward from the said engagements at each end, whereby a coupleis provided at each end tending to rotate theendv sections, and meansconnecting the sections together and balancing themoments of saidcouples.

4. A floating dry dock comprising two buoyantend sections and at leastone buoyant intermediate section, all in end to end relation, therebeing an upper horizontally projecting part on a said intermediatesection adjacent to one endsection and. asimilar upper horizontallyprojecting part ona said intermediate section adjacent.

to the other end section, and a lower horizontally projecting part oneach end section. extending throughout the Width of the end section, andmeans detachably connecting each end section to an intermediate sectionwith a said lower projecting part of an end section under and spaced asubstantial vertical distance below a said upper projecting part of anintermediate section, thereby to provide a passage between themtransverse- 1y of the dry dock, said upper and lower horizontallyprojecting parts spacing the main bodies of adjacent sectionslongitudinally apart, with the center of buoyancy of each end sectionspaced a substantial distance outward from said upper projecting part ofthe adjacent intermediate section.

5. A floating dry dock comprising a plurality of buoyant sections in endto end relation, one of said sections having an upper horizontally pro-8 jectingpai t-and the adjacent section. having a lower horizontallyprojecting part extending throughout the width of the section, means forreleasably connecting said adjacent sections together with said lowerprojecting part of one section underand spaced a substantial verticaldistance below said upper projecting part of the adjacent. section andwith the bottoms of the section approximately in a common plane, therebyto provide a substantial transverse passageway between said projectingparts when the sections. are connected for dry docking a hull; saidconnecting means including a plurality of vertically spaced connectingelements on each of the connected sections whereby adjacent sections maybe connected with their bottom surfaces in any of a plurality ofdifierent relative positions by selection of predetermined ones of saidconnecting elements for effecting the connection.

JAMES STUART CRANDALL.

REFEREIWJES CITED Thefollowing references are of record in the file ofthis patent:

UNITED STATES PATENTS Number- Name Date 710,765 Cunningham Oct. 7, 19027-36.;732- I-Iylander Aug. 18, 1903 2,291,078 Harris July 28, 19422,325,607 Harris Aug. 3, 1943 FOREIGN PATENTS Number Country Date 23,819Great Britain 1905 29,601 Great Britain 1913 126,189 Austria Jan. 11,1932 197,082 Great Britain May 10, 1923

